ISO 3744

Sound power — enveloping surface engineering method

ISO 3744 specifies the engineering method for determining sound power and sound energy levels using sound pressure measurements obtained on an imaginary surface (hemispherical or parallelepiped) surrounding a noise source. This method is widely used for in-situ testing of machinery, industrial equipment, and large installations where reverberation room testing is impractical. It provides a practical balance between accuracy and field applicability, making it suitable for machinery compliance testing, environmental noise assessments, and product CE marking requirements across the EU. ISO 17025 accreditation confirms laboratory proficiency in sound field measurement, environmental parameter correction, and uncertainty quantification for this complex measurement method.

What it measures

  • Sound power level (Lw) using enveloping surface pressure data
  • A-weighted and frequency-weighted sound power
  • Octave and one-third-octave band sound power (63 Hz to 8 kHz)
  • Environmental and measurement corrections
  • Sound power directivity and spatial variability
🇩🇪 DIN EN ISO 3740 🇬🇧 BS EN ISO 3740 🇫🇷 NF EN ISO 3740 🇮🇹 UNI EN ISO 3740 🇪🇸 UNE EN ISO 3740 🇳🇱 NEN EN ISO 3740 🇩🇪 DIN EN ISO 3743-1 🇬🇧 BS EN ISO 3743-1 🇫🇷 NF EN ISO 3743-1 🇮🇹 UNI EN ISO 3743-1 🇪🇸 UNE EN ISO 3743-1 🇳🇱 NEN EN ISO 3743-1
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DAkkS D-PL-21039-04-04 Erlangen, DE
DIN EN ISO 10304-1 DIN EN ISO 11885 DIN EN ISO 15350 DIN EN ISO 15351 DIN EN ISO 17294-2 + 3 more
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DAkkS D-K-21039-01-00 Erlangen, DE
- Gleichspannung Messgeräte 0,33 V bis < 3,3 V 330 V Quellen > 0,1 V + 3 more
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UKAS 4155 Sunderland, GB
5 of HSG 227 (2004) (HSG 264, 2012)
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DAkkS D-K-17452-01-00 Schalkau, DE
Kraft (WPM) 30 N Vibration measuring instruments — test m maschinen nach DIN Kraft * 10 N Acoustics — tonality assessment (DIN 456 + 3 more
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DAkkS D-PL-11140-11-01 Stuttgart, DE
DIN EN ISO 717-1 DIN EN ISO 717-2 DIN EN ISO 10140-1 DIN EN ISO 10140-2 DIN EN ISO 10140-3 + 3 more
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DAkkS D-PL-11140-14-00 Braunschweig, DE
DIN ISO 16000-3 DIN EN ISO 12460-3 DIN EN ISO 12460-4 DIN EN ISO 12460-5 100 HV 120 + 3 more
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DAkkS D-K-11140-02-00 Freiburg, DE
Tensile testing of metallic materials (I Vickers hardness test (ISO 6507) Kurzschlussstrom Solarmodule 16 mA Gleichstrom- und Nieder- 10 mV + 3 more
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DAkkS D-ML-13455-01-00 Dubai, AE
HbF HbA1c HbA2 HBB/HBD Anti-HBs + 3 more
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Fugro GB

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UKAS 0919 Wallingford, GB
BS 1377: Part 2: 1990 BS 1377-3:2018 + A1:2021 ASTM D4186-12: 2020 ASTM D5334-22 ASTM D2216-19 + 3 more
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UKAS 10287 Chelmsford, GB
(HSG 264, 2012)
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UKAS 0580 Bexhill, GB
FLOW Gas pressure (absolute) Gas pressure (gauge) DC CURRENT TEMPERATURE + 3 more
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DAkkS D-K-15109-01-01 Titisee-Neustadt, DE
Druck * Absolutdruck Pabs 1 bar; 3 bar Negativer und positiver Überdruck + 3 more
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UKAS 2083 Wellington, GB
(HSG 248) – 2021 M4 based on HSG 248 (PCM) based on HSG 248 M3 based on HSG 248 (HSG 264, 2012) + 1 more
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G&M Procter

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UKAS 2727 Perth, GB
based on ISO 11133:2014+Amd dependent) based on BS EN based on BS EN 12322:1999
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UKAS 4037 Welwyn Garden City, GB
(HSG 248) – 2021 (PCM) based on HSG 248 PRO02 based on HSG 248
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DAkkS D-PL-14170-01-03 Hamburg, DE
DIN EN 12579 DIN 19698-1 DIN 19698-2 DIN 51750-2 DIN ISO 11277 + 3 more
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ENAC LE2121 Llinars del Valles, ES
ISO 9994 ISO 22702 ASTM F400 ASTM F2201
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DAkkS D-PL-19633-01-00 Dresden, DE
DIN 38402-A 12 DIN EN ISO 5667-6 (A 15) DIN 38402-A 30 DIN EN ISO 5667-13 (S 1) DIN 38414-S 11 + 3 more
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DAkkS D-PL-17559-01-00 Bexbach, DE
DIN EN 50173-1 DIN EN 50173-2 DIN EN 50173-3 DIN EN 50173-4 DIN EN 50173-5 + 3 more
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GIKE

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ENAC LE614 Donostia-San Sebastián, ES
UNE-EN 12390-2 UNE-EN 12350-1 UNE-EN 1744-1 UNE-EN 933-1 UNE-EN 933-8 + 3 more
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GINGER CEBTP

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COFRAC 1-0002 Elancourt, FR
DIN EN 1097-1 DIN EN ISO 10140-2 DIN EN 933-3 DIN EN 1097-2 DIN EN ISO 10140-4 + 3 more
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GINGER LECES

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COFRAC 1-7433 Saint-Julien-Les-Metz, FR
DIN EN 14385 ETSI EN 301 489-1 V2.2.3 2019-11 NF X43-551 IS EN 1948-1:2006 2006 DIN EN 14789 + 3 more
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COFRAC 1-6437 Évreux Cedex, FR
NF T 90-412 DIN EN ISO 7899-1 NF U47-101 DIN ISO 11465 DIN EN ISO 6888-2 + 3 more
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COFRAC 1-5684 Saint-Contest, FR
DIN EN ISO 17294-2 DIN 51750-3 DIN EN ISO 14403-2 NF EN ISO 54321 et NF T 90-412 + 3 more
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COFRAC 1-6185 Saint-Lô Cedex, FR
DIN ISO 17289 NF X 31-615 ISO 15648 ISO BS EN 3727-1:2002 ASTM D 7238 + 3 more
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Industries

Industrial machinery manufacturers Construction equipment producers HVAC and ventilation systems Power generation and compressor suppliers Large transport and handling equipment makers

Related Standards

  • ISO 3740 Acoustics — Determination of sound power levels of noise sources — General guidelines
  • ISO 3743-1 Acoustics — Determination of sound power levels of noise sources — Part 1: Reverberation room method
  • ISO 3745 Acoustics — Determination of sound power levels of noise sources — Precision method using an enveloping surface

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